Vaccine induces cocaine immunity in mice

Cocaine immunity has been induced in mice using an altered version of the common cold virus. The vaccine could be used to break cocaine addiction in humans.

The vaccine contained in the virus trains the body's defences to see cocaine molecules as intruders, and so the immune system destroys the cocaine molecules before they can reach the brain.

Researchers hooked modified cocaine molecules onto an adenovirus. They also discarded the components of the virus that cause sickness, leaving only those that cause an immune response.

When injected into mice, the virus caused the immune system to produce antibodies to cocaine. Antibody production is part of the body's natural response to potentially harmful bacteria and viruses. When these antibodies were put in a test tube with cocaine molecules they were found to engulf the cocaine. The vaccine had trained the antibodies to see cocaine molecules as intruders.

As the immune response destroys the drug before it reaches the brain's pleasure centre, it is hoped the vaccine could help those addicted to cocaine to kick the habit. The effects of the vaccine in mice last for at least 13 weeks.

Researchers also tested the effect of the vaccine on mouse behaviour. Those given the vaccine were much less hyperactive when on cocaine than those not vaccinated.

It is hoped the vaccine will quickly move into human trials. Similar vaccines could be developed against addictions to nicotine, heroin and other opiates.